Conventionally, according to a planographic stencil (screen) type printing for printing, for example, solder paste on lands of a printed circuit board, as shown in FIG. 18A and FIG. 18B, a screen mask (metal mask) 1 having through holes 1a arranged in a specified pattern in correspondence with lands 5 of the printed circuit board 4 is placed in a specified position on the board 4 while being brought in contact with the board. Next, as shown in FIG. 18C, FIG. 19A and FIG. 19B, solder paste 2 is supplied to one end of the screen mask 1, and this solder paste 2 is moved by a squeegee 3 from the one end of the screen mask 1 in a specified direction, thereby filling the solder paste 2 into each through hole 1a of the screen mask 1. Next, as shown in FIG. 18D, the screen mask 1 is separated from the board 4 so as to move the solder paste 2 inside the through holes 1a of the screen mask 1 onto the lands 5 of the board 4, thereby forming solder paste layers 2a on the lands 5 of the board 4 as shown in FIG. 18E.
However, according to the above structure, as shown in FIG. 19C, part of the solder paste 2 is left inside the through hole la of the screen mask 1 while adhering to the inner wall of the through hole due to the viscosity of the solder paste itself when the screen mask 1 is separated from the board 4, and this disadvantageously causes a phenomenon that the solder paste continuously extends across the left solder paste 2 and the solder paste 2 placed on the land 5 of the board 4. Consequently, as the screen mask 1 moves away from the board 4, the relative deformation (shear rate gradient) of the continuously extending solder paste increases to be pulled and broken at an arbitrary portion between the screen mask 1 and the board 4. Part of the solder paste that has been pulled and broken adheres to a portion other than the land 5 on the board 4 as shown in FIG. 19D and adheres to the peripheral portion of the through hole 1a on the rear surface of the screen mask 1 on the board side. This has disadvantageously caused a printing blur in the next printing stage, the occurrence of a bridge defined by the inadvertent adhesion of the solder paste to the adjacent solder paste layer 2a on the board 4, and the insufficient formation of a solder paste layer on the board due to the adhesion of the solder paste to the screen mask.
Accordingly, the object of the present invention is to solve the aforementioned issues and provide a printing method and printing apparatus capable of accurately pulling and breaking the printing paste between the stencil on which the printing paste is retained and the board while causing no bridging, causing no printing blur attributed to the printing paste left on the stencil side and causing no shortage of supply of the printing paste onto the board.